Until the 2000 Edition of API-579 , the geometries (Ri/t, a/ℓ, a/t in cylinders or spheres) for which a complete set of stress intensity factor influence coefficients (Gi) existed was limited. To bridge that gap, many analysts have used the G0 and G1 coefficients for flat plate geometries to represent axial or circumferential flaws in cylinders. Because the cylindrical geometry contains additional stiffness effects due to curvature, it was generally assumed that the plate geometry (Ri/t = ∞) will be bounding and therefore conservative .
Since 2007, extensive sets of Gi coefficient have been published for plates, cylinders and spheres based on finite element models. These coefficients for cylinders have been curve fit and are available in Appendix A of the ASME Boiler and Pressure Vessel Code, Section XI . This paper compares the G0 coefficients at the deepest point of semi-elliptical flaws from a plate to those for an OD and ID circumferential flaw in a cylinder to confirm the conservatism of the G0 coefficients from a plate geometry.